Fuel supply system

Abstract

A fuel supply system for mixture-compressing internal combustion engine with externally-supplied ignition is proposed, which serves to form the most optimal possible fuel-air mixture. The fuel supply system includes a primary mixture formation unit disposed in the intake manifold and at least one ultrasonic atomizer nozzle in the intake manifold, for the purpose of correcting the fuel-air mixture by means of supplementary fuel, downstream of the primary mixture unit or in each individual intake tube. The ultrasonic atomizer nozzles are triggered, with the interposition of an electronic control device, in accordance with operating characteristics of the engine, as well as the exhaust composition, and they permit the supply of finely prepared supplementary fuel for the purpose of regulating the fuel-air mixture to a predetermined λ value; of compensating for non-uniform distribution, and of enrichment of the mixture in the case of warm-up, full load and acceleration, as well as of idling regulation.

What is claimed and desired to be secured by Letters Patent of the United States is: 
     
       1. A fuel supply system for a mixture-compressing internal combustion plural cylinder engine having internally-supplied ignition, and including a primary mixture formation unit disposed in a common intake tube having branches leading to individual cylinders of said engine and at least one supplementary mixture formation unit also disposed in each of the branches thereof, characterized in that at least one ultrasonic atomizer nozzle serves as said supplementary mixture formation unit and is disposed in said intake tube branch downstream of said primary mixture formation unit, triggering of each of said ultrasonic atomizer nozzles is effected by programmable means stored in a memory of an electronic control device, said memory having stored therein a performance graph showing the non-uniform distribution of the mixture to the individual cylinders of said engine, and said engine further including individual exhaust manifold lines, and exhaust sensor means in each of said lines for detecting oxygen content in the exhaust gas, and for controlling said at least one ultrasonic atomizer nozzle via said electronic control device. 
     
     
       2. A fuel supply system as defined by claim 1, characterized in that triggering time of said ultrasonic atomizer nozzles can be additively prolonged for the purpose of the warm-up, full load, and acceleration enrichment of the fuel-air mixture. 
     
     
       3. A fuel supply system as defined by claim 1, characterized in that pressure of fuel delivered to said ultrasonic atomizer nozzle is variable in accordance with engine load and rpm. 
     
     
       4. A fuel supply system as defined by claim 1, in that each one of said intake tube branches has an inner wall area, said inner wall area further including means arranged to reduce a portion of the cross-section of said wall area and said ultrasonic atomizer disposed at said reduced portion of said wall area. 
     
     
       5. A fuel supply system as defined by claim 1, characterized in that said ultrasonic atomizer nozzle further includes a frustoconical oscillation amplification body provided with an axial bore, said bore having a spring loaded valve element arranged to cooperate with a valve seat therein and said body further including a piezo-ceramic disc at one end and an atomizer plate at another end. 
     
     
       6. A fuel supply system as defined by claim 1, characterized in that said ultrasonic atomizer nozzle is triggerable by said electronic control device in accordance with engine rpm so that when the rpm drops below a predetermined rpm, supplementary fuel can be delivered via the ultrasonic atomizer nozzle until the desired idling rpm has again been attained.